netlink.h

linux 内核源代码

 * See nla_parse()
 */
static inline int nla_parse_nested(struct nlattr *tb[], int maxtype,
				   struct nlattr *nla,
				   const struct nla_policy *policy)
{
	return nla_parse(tb, maxtype, nla_data(nla), nla_len(nla), policy);
}

/**
 * nla_parse_nested_compat - parse nested compat attributes
 * @tb: destination array with maxtype+1 elements
 * @maxtype: maximum attribute type to be expected
 * @nla: attribute containing the nested attributes
 * @data: pointer to point to contained structure
 * @len: length of contained structure
 * @policy: validation policy
 *
 * Parse a nested compat attribute. The compat attribute contains a structure
 * and optionally a set of nested attributes. On success the data pointer
 * points to the nested data and tb contains the parsed attributes
 * (see nla_parse).
 */
static inline int __nla_parse_nested_compat(struct nlattr *tb[], int maxtype,
					    struct nlattr *nla,
					    const struct nla_policy *policy,
					    int len)
{
	if (nla_len(nla) < len)
		return -1;
	if (nla_len(nla) >= NLA_ALIGN(len) + sizeof(struct nlattr))
		return nla_parse_nested(tb, maxtype,
					nla_data(nla) + NLA_ALIGN(len),
					policy);
	memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
	return 0;
}

#define nla_parse_nested_compat(tb, maxtype, nla, policy, data, len) \
({	data = nla_len(nla) >= len ? nla_data(nla) : NULL; \
	__nla_parse_nested_compat(tb, maxtype, nla, policy, len); })
/**
 * nla_put_u8 - Add a u8 netlink attribute to a socket buffer
 * @skb: socket buffer to add attribute to
 * @attrtype: attribute type
 * @value: numeric value
 */
static inline int nla_put_u8(struct sk_buff *skb, int attrtype, u8 value)
{
	return nla_put(skb, attrtype, sizeof(u8), &value);
}

/**
 * nla_put_u16 - Add a u16 netlink attribute to a socket buffer
 * @skb: socket buffer to add attribute to
 * @attrtype: attribute type
 * @value: numeric value
 */
static inline int nla_put_u16(struct sk_buff *skb, int attrtype, u16 value)
{
	return nla_put(skb, attrtype, sizeof(u16), &value);
}

/**
 * nla_put_u32 - Add a u32 netlink attribute to a socket buffer
 * @skb: socket buffer to add attribute to
 * @attrtype: attribute type
 * @value: numeric value
 */
static inline int nla_put_u32(struct sk_buff *skb, int attrtype, u32 value)
{
	return nla_put(skb, attrtype, sizeof(u32), &value);
}

/**
 * nla_put_64 - Add a u64 netlink attribute to a socket buffer
 * @skb: socket buffer to add attribute to
 * @attrtype: attribute type
 * @value: numeric value
 */
static inline int nla_put_u64(struct sk_buff *skb, int attrtype, u64 value)
{
	return nla_put(skb, attrtype, sizeof(u64), &value);
}

/**
 * nla_put_string - Add a string netlink attribute to a socket buffer
 * @skb: socket buffer to add attribute to
 * @attrtype: attribute type
 * @str: NUL terminated string
 */
static inline int nla_put_string(struct sk_buff *skb, int attrtype,
				 const char *str)
{
	return nla_put(skb, attrtype, strlen(str) + 1, str);
}

/**
 * nla_put_flag - Add a flag netlink attribute to a socket buffer
 * @skb: socket buffer to add attribute to
 * @attrtype: attribute type
 */
static inline int nla_put_flag(struct sk_buff *skb, int attrtype)
{
	return nla_put(skb, attrtype, 0, NULL);
}

/**
 * nla_put_msecs - Add a msecs netlink attribute to a socket buffer
 * @skb: socket buffer to add attribute to
 * @attrtype: attribute type
 * @jiffies: number of msecs in jiffies
 */
static inline int nla_put_msecs(struct sk_buff *skb, int attrtype,
				unsigned long jiffies)
{
	u64 tmp = jiffies_to_msecs(jiffies);
	return nla_put(skb, attrtype, sizeof(u64), &tmp);
}

#define NLA_PUT(skb, attrtype, attrlen, data) \
	do { \
		if (nla_put(skb, attrtype, attrlen, data) < 0) \
			goto nla_put_failure; \
	} while(0)

#define NLA_PUT_TYPE(skb, type, attrtype, value) \
	do { \
		type __tmp = value; \
		NLA_PUT(skb, attrtype, sizeof(type), &__tmp); \
	} while(0)

#define NLA_PUT_U8(skb, attrtype, value) \
	NLA_PUT_TYPE(skb, u8, attrtype, value)

#define NLA_PUT_U16(skb, attrtype, value) \
	NLA_PUT_TYPE(skb, u16, attrtype, value)

#define NLA_PUT_LE16(skb, attrtype, value) \
	NLA_PUT_TYPE(skb, __le16, attrtype, value)

#define NLA_PUT_U32(skb, attrtype, value) \
	NLA_PUT_TYPE(skb, u32, attrtype, value)

#define NLA_PUT_BE32(skb, attrtype, value) \
	NLA_PUT_TYPE(skb, __be32, attrtype, value)

#define NLA_PUT_U64(skb, attrtype, value) \
	NLA_PUT_TYPE(skb, u64, attrtype, value)

#define NLA_PUT_STRING(skb, attrtype, value) \
	NLA_PUT(skb, attrtype, strlen(value) + 1, value)

#define NLA_PUT_FLAG(skb, attrtype) \
	NLA_PUT(skb, attrtype, 0, NULL)

#define NLA_PUT_MSECS(skb, attrtype, jiffies) \
	NLA_PUT_U64(skb, attrtype, jiffies_to_msecs(jiffies))

/**
 * nla_get_u32 - return payload of u32 attribute
 * @nla: u32 netlink attribute
 */
static inline u32 nla_get_u32(struct nlattr *nla)
{
	return *(u32 *) nla_data(nla);
}

/**
 * nla_get_be32 - return payload of __be32 attribute
 * @nla: __be32 netlink attribute
 */
static inline __be32 nla_get_be32(struct nlattr *nla)
{
	return *(__be32 *) nla_data(nla);
}

/**
 * nla_get_u16 - return payload of u16 attribute
 * @nla: u16 netlink attribute
 */
static inline u16 nla_get_u16(struct nlattr *nla)
{
	return *(u16 *) nla_data(nla);
}

/**
 * nla_get_le16 - return payload of __le16 attribute
 * @nla: __le16 netlink attribute
 */
static inline __le16 nla_get_le16(struct nlattr *nla)
{
	return *(__le16 *) nla_data(nla);
}

/**
 * nla_get_u8 - return payload of u8 attribute
 * @nla: u8 netlink attribute
 */
static inline u8 nla_get_u8(struct nlattr *nla)
{
	return *(u8 *) nla_data(nla);
}

/**
 * nla_get_u64 - return payload of u64 attribute
 * @nla: u64 netlink attribute
 */
static inline u64 nla_get_u64(struct nlattr *nla)
{
	u64 tmp;

	nla_memcpy(&tmp, nla, sizeof(tmp));

	return tmp;
}

/**
 * nla_get_flag - return payload of flag attribute
 * @nla: flag netlink attribute
 */
static inline int nla_get_flag(struct nlattr *nla)
{
	return !!nla;
}

/**
 * nla_get_msecs - return payload of msecs attribute
 * @nla: msecs netlink attribute
 *
 * Returns the number of milliseconds in jiffies.
 */
static inline unsigned long nla_get_msecs(struct nlattr *nla)
{
	u64 msecs = nla_get_u64(nla);

	return msecs_to_jiffies((unsigned long) msecs);
}

/**
 * nla_nest_start - Start a new level of nested attributes
 * @skb: socket buffer to add attributes to
 * @attrtype: attribute type of container
 *
 * Returns the container attribute
 */
static inline struct nlattr *nla_nest_start(struct sk_buff *skb, int attrtype)
{
	struct nlattr *start = (struct nlattr *)skb_tail_pointer(skb);

	if (nla_put(skb, attrtype, 0, NULL) < 0)
		return NULL;

	return start;
}

/**
 * nla_nest_end - Finalize nesting of attributes
 * @skb: socket buffer the attributes are stored in
 * @start: container attribute
 *
 * Corrects the container attribute header to include the all
 * appeneded attributes.
 *
 * Returns the total data length of the skb.
 */
static inline int nla_nest_end(struct sk_buff *skb, struct nlattr *start)
{
	start->nla_len = skb_tail_pointer(skb) - (unsigned char *)start;
	return skb->len;
}

/**
 * nla_nest_compat_start - Start a new level of nested compat attributes
 * @skb: socket buffer to add attributes to
 * @attrtype: attribute type of container
 * @attrlen: length of structure
 * @data: pointer to structure
 *
 * Start a nested compat attribute that contains both a structure and
 * a set of nested attributes.
 *
 * Returns the container attribute
 */
static inline struct nlattr *nla_nest_compat_start(struct sk_buff *skb,
						   int attrtype, int attrlen,
						   const void *data)
{
	struct nlattr *start = (struct nlattr *)skb_tail_pointer(skb);

	if (nla_put(skb, attrtype, attrlen, data) < 0)
		return NULL;
	if (nla_nest_start(skb, attrtype) == NULL) {
		nlmsg_trim(skb, start);
		return NULL;
	}
	return start;
}

/**
 * nla_nest_compat_end - Finalize nesting of compat attributes
 * @skb: socket buffer the attributes are stored in
 * @start: container attribute
 *
 * Corrects the container attribute header to include the all
 * appeneded attributes.
 *
 * Returns the total data length of the skb.
 */
static inline int nla_nest_compat_end(struct sk_buff *skb, struct nlattr *start)
{
	struct nlattr *nest = (void *)start + NLMSG_ALIGN(start->nla_len);

	start->nla_len = skb_tail_pointer(skb) - (unsigned char *)start;
	return nla_nest_end(skb, nest);
}

/**
 * nla_nest_cancel - Cancel nesting of attributes
 * @skb: socket buffer the message is stored in
 * @start: container attribute
 *
 * Removes the container attribute and including all nested
 * attributes. Returns -1.
 */
static inline int nla_nest_cancel(struct sk_buff *skb, struct nlattr *start)
{
	return nlmsg_trim(skb, start);
}

/**
 * nla_validate_nested - Validate a stream of nested attributes
 * @start: container attribute
 * @maxtype: maximum attribute type to be expected
 * @policy: validation policy
 *
 * Validates all attributes in the nested attribute stream against the
 * specified policy. Attributes with a type exceeding maxtype will be
 * ignored. See documenation of struct nla_policy for more details.
 *
 * Returns 0 on success or a negative error code.
 */
static inline int nla_validate_nested(struct nlattr *start, int maxtype,
				      const struct nla_policy *policy)
{
	return nla_validate(nla_data(start), nla_len(start), maxtype, policy);
}

/**
 * nla_for_each_attr - iterate over a stream of attributes
 * @pos: loop counter, set to current attribute
 * @head: head of attribute stream
 * @len: length of attribute stream
 * @rem: initialized to len, holds bytes currently remaining in stream
 */
#define nla_for_each_attr(pos, head, len, rem) \
	for (pos = head, rem = len; \
	     nla_ok(pos, rem); \
	     pos = nla_next(pos, &(rem)))

/**
 * nla_for_each_nested - iterate over nested attributes
 * @pos: loop counter, set to current attribute
 * @nla: attribute containing the nested attributes
 * @rem: initialized to len, holds bytes currently remaining in stream
 */
#define nla_for_each_nested(pos, nla, rem) \
	nla_for_each_attr(pos, nla_data(nla), nla_len(nla), rem)

#endif